i did research on this back when i was a smoker. and the problem is that no matter how isolated from him your smoking is unless you change your clothes and wash you body off after you smoke whenever you go near him you are putting his lungs in danger. their lungs are much smaller than ours and the lingering residue of smoke/nicotine on your body and clothes affects him 20 times more than you. The best thing you could do is smoke outside which is what i started doing for the sake of all my animals, and wash you hands as much as possible after you smoke/before you handle him. if you are smoking outside not as much of the smell attaches to your clothes because of the better air circulation.
I would have to agree with Brian on this. As long as you are anywhere near your beardie and smoking.... they are affected! There is no two ways about it. If you must smoke in your home, keep the door closed to the room Roo is in. As mentioned, their lungs are very tiny, so the affect on them would be much worse than second hand smoke for us(with larger lungs).